Chapter 10 (Muscular Tissue V)

Question 1

Contractile (Motor) Proteins

Answer 1

Myosin and Actin

Question 2

Myosin

Answer 2

Thick filaments
Functions as a motor protein which can achieve motion
Convert ATP to energy of motion
Projections (heads) of each myosin molecule protrude outward

Question 3

Actin

Answer 3

Thin filaments
Actin molecules provide a site where a myosin head can attach
Allows muscle contraction to begin

Question 4

Regulatory Proteins

Answer 4

Troponin and Tropomyosin

Question 5

Troponin and Tropomyosin

Answer 5

Lie on the thin filaments
Tropomyosin covers sites where myosin binds to actin
Block attachment of myosin heads to actin binding sites
When Calcium ions bind to troponin, the tropomyosin moves and exposes the myosin binding sites on actin
When the attached myosin molecule changes shape, contraction occurs

Question 6

Structural Proteins

Answer 6

Titin and Dystrophin

Question 7

Titin

Answer 7

Stabilize the position of myosin

Accounts for much of the elasticity and extensibility of myofibrils

Question 8

Dystrophin

Answer 8

Links thin filaments to the sarcolemma